1. Field of the Invention
The present invention relates to a parking brake system, particularly a parking brake system that unlocks a parking gear using an operational force converted from hydraulic pressure that is generated when the engine starts and an operational force by an electromagnetic force, and automatically locks the parking gear using an operational force converted from hydraulic pressure that is generated when the engine stops and an operational force by an electromagnetic force.
2. Description of Related Art
In general, a parking brake system in a vehicle, which is provided to secure a safe stop or parking by restricting movement of the vehicle when stopping or parking the vehicle, forcibly restricts the rear wheels as an operation lever is operated.
Further, in vehicles equipped with an automatic transmission, a parking brake system, which can selectively restrict rotation of a parking gear in the transmission as the shift lever is operated, may be used. According to parking brake systems for an automatic transmission in the related art, the parking gear is restricted by an initial force by hydraulic pressure and a locking mechanism that maintains the restriction of the parking gear using magnetization by an electromagnet.
Therefore, in parking brake systems for an automatic transmission in the related art, it is required to use an operational force by hydraulic pressure and an electromagnet and a locking mechanism is additionally needed to maintain restriction of the parking gear by magnetization of the electromagnet. Accordingly, the configuration is complicated and the parking brake systems cannot normally function when any one of the hydraulic system, the mechanical part and the locking part for maintaining the restriction is damaged by magnetization of the electromagnet.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.